# How much weight do you feel during negative g-forces?

My physics teacher told me and some other students that when you experience negative g-forces, your weight equals: $$\frac{mass}{g_{force}}$$ So when the g-forces equal -4 g your mass will be: $$\frac{mass}{-4}$$ Now I don't think this is true, because this doesn't work when the g-forces are positive. And also to follow the pattern (example pattern):)

$$45 \, \mathrm{kg} \times 3g = 1350\, \mathrm N$$

$$45 \, \mathrm{kg} \times 2g = 900\, \mathrm N$$

$$45 \, \mathrm{kg} \times 1g = 450 \, \mathrm N$$

$$45 \, \mathrm{kg} \times 0g = 0\, \mathrm N$$

$$45 \, \mathrm{kg} \times (-1g) = -450\, \mathrm N$$

$$45 \, \mathrm{kg}\ /\;(-1g) = -450 \, \mathrm N$$

$$45 \, \mathrm{kg} \times (-2g) = -900\, \mathrm N$$

$$45 \, \mathrm{kg}\ / \;(-2g) = -225\, \mathrm N$$

Which one is true?

• Either you have misunderstood your teacher, or the teacher made a mistake. You appear to be familiar with $F=ma$, and that equation is valid for positive & negative accelerations. – PM 2Ring Sep 21 at 20:42
• @PM2Ring Yeha, to be honest my teacher told some friends who told me so there may have been some misinterpretation but idk. Thought it sounded weird anyway – Melvin Sep 21 at 21:15
• @PM2Ring so in conclusion the patter with f=ma is correct? – Melvin Sep 21 at 21:17

The pattern with $$F=ma$$ is the correct one. The g-force experienced by an object can be written as $$F = n(mg)$$ where m is the mass; n is the number of g's and g is the gravitational constant. When n is greater than 1 the object will experience a force greater than the usual gravitational attraction of Earth; if we were to measure its weight with a scale when experiencing said force its apparent mass weight would be greater than if it were only under the effects of gravity (which corresponds to n=1). For $$0 < n < 1$$ an object would be under the influence of a force smaller than the one exerted by gravity; therefore, if we were to weight the object it would be lighter than usual. As you may have noticed the case of n=0 corresponds to the feeling of weightlessness which is what astronauts feel and corresponds to no apparent weight.